The present invention relates to an asphalt composition. The present invention also relates to a vibration-damping sheet formed by the asphalt composition. It relates more particularly to an asphalt composition comprising a straight asphalt, a specific liquid rubber, a filler and, if necessary, a resinous tackifier, which has excellent physical properties, particularly heat-resistance, cold-resistance and anti-corrosion characteristics.
Heretofore, elastomers have been incorporated into straight asphalt for the modification thereof. These elastomers, however, generally have high viscosities and poor miscibility with asphalt. It is difficult to uniformly disperse such elastomers into asphalt. In the conventional method, liquid rubber having hydroxy groups at the molecule terminals is reacted with straight asphalt by the use of a cross-linking agent, such as diisocyanate. This method, however, has disadvantages in that diisocyanate has high toxicity and poor stability, and thus inconveniences are involved in handling.
In order to prevent vibration of floors of cars and of other substrates, it is effective to heat-bond a vibration-damping sheet formed by molding an asphalt composition, on such substrates. Conventional vibration-damping sheets, however, suffer from the disadvantages of the narrow temperature range in which a satisfactory vibration-preventing effect can be maintained and of their poor quality particularly with regard to reproducibility.